Renal failure is one of the most common medical conditions veterinarians treat. Technicians are often needed to help facilitate those treatments and explain the treatments to the owners. This blog is a brief review on chronic renal failure, treatments, and long-term management goals.
1) Overview: What is chronic renal failure? Chronic means that the kidney function has slowly decreased over time (months to years). It is a progressive loss of kidney function which cannot be cured. The kidneys are not able to properly filter waste products from the body. Typically the kidneys have lost more than 70% of functional capacity before clinical signs are seen. Symptoms may include polyuria and polydipsia, weight loss, poor haircoat, chronic or intermittent vomiting, and decreased appetite. Labwork typically shows azotemia (elevated BUN and creatinine which are the two renal values), dilute urine (low urine specific gravity due to the kidneys not being able to concentrate), elevated phosphorus, and sometimes anemia. The kidneys make erythropoetin (EPO a hormone which helps in production of new red blood cells). When kidney function decreases, so does EPO production, hence development of anemia.
2) Management: The goal of treatments for CRF is to provide a quality of life for the patient for as long as possible. Medical management of chronic renal failure consists of several things.
- Fluid support for the kidneys is probably the most important treatment. This helps support hydration status. Often owners can be taught how to administer subcutaneous fluids to their pet (especially cats) once or twice weekly at home.
- Acid blockers such as famotidine (Pepcid AC) are very helpful. Pets in renal failure are at risk for ulceration in the gastrointestinal tract and should be on a daily acid reducer.
- Diet should be low in protein and phosphorus. There are various prescription diets in this category that may be used. These diets reduce the workload on the kidneys and can help slow the progression of the disease.
- Blood pressure monitoring is crucial. Hypertension will develop in more than 20% of patients with chronic renal failure. High blood pressure can cause further renal damage, can cause blood clots, blindness (from retinal damage), and can lead to heart disease or other problems. Patients with hypertension need to be on medication to manage this problem.
- Iron supplements can be helpful in anemic patients. Blood transfusions are usually not helpful, as these are not beneficial long term, and the anemia is chronic in nature.
- If the phosphorus level is elevated, a phosphorus binder can be used to reduce this level. Elevated phosphorus can make the patient nauseous.
- Azodyl is a supplement that has been said to bind uremic toxins so that they are excreted in the intestine (an enteric dialysis). While there may be some controversy on benefit, many owners report an improved quality of life with this supplement.
- Sometimes other things are needed. CRF often leads to potassium depletion and a potassium supplement may be needed.
3) Ultimately, quality of life is what we always strive for. The goal is to keep the patient eating and minimize nausea. The veterinarian should provide education to the owner of things to watch for as the disease progresses so that they know what to expect in preparation for making end of life decisions. Treatments must be tailored to the individual patient.